Republican attempts to cut billions of dollars in food assistance to poor American families have been denounced as an “abomination” and “immoral” by Democrats who have vowed to block the measure in Congress.

The cuts, part of a five-year farm bill under debate in the House of Representatives agricultural committee on Wednesday, slash $16bn from the food stamp programme over the next decade.

The move appears intended in part to highlight Republican disparagement of Barack Obama as the “food stamp president” because record numbers of Americans now claim the benefit, doubling the cost of the programme since 2008 to $80bn a year.

More than 46 million Americans receive food stamps, nearly half of them children.

The agricultural committee chairman, Frank Lucas, justified the cuts in part by claiming that the system has been manipulated by some US states to have the federal government provide food to households not entitled to assistance under what is formally called the Supplemental Nutrition Assistance Program (Snap).

“Snap’s resources have been stretched because this administration has encouraged states to take liberties in how the programme is administered,” he said at the hearing to consider the bill.

“I’d like to be clear that this legislation will not prevent families that qualify for assistance under Snap law from receiving their benefits. We are working to better target the programme and improve its integrity so that families most in need can continue to receive nutrition assistance.”

But the proposal has met with strong objection from some Democrats.

Congressman Jim Clyburn, the third most powerful Democrat in the House of Representatives said: “For us to be marking up this farm bill with this big a cut in Snap programs is an abomination”.

“I know what it is to try and teach world history when you know the students in front of you did not eat breakfast,” Clyburn said. “We should not set ourselves up as protectors of the wealthy, which seems to be what we are doing in this farm bill.”

Congresswoman Rosa DeLauro, a member of the committee that funds administration of the food stamp programme, said up to 3 million people would lose access to the programme and almost 300,000 children would lose access to free school meals.

She said: “These proposed cuts show a total disregard for the real impact they would have on hungry kids and families across the country … This is immoral. We have to stop these cuts. We cannot let American families face the threat of hunger.”

Lynn Woolsey was one of several Democratic members of Congress who defended the food stamp programme because at one time she relied on it.

“This is personal for me. When my husband walked out on us, my pay cheque wasn’t enough. I enrolled in the food stamp programme not because I wanted to but because I had to.”

Representative Joe Baca said: “I received food stamps. I’m not proud of it, but the fact is, I did, and that makes me a warrior for those who need it.”

But the leading Democrat on the committee, Collin Peterson, suggested that the cuts might remain in the legislation for now because it needs to pass by next month in time to replace the existing farm bill, which expires in September. He has said he expects the Senate to remove the cuts to food stamps when it considers the bill.

“I remain concerned with the proposed changes to nutrition programmes. There are better, more responsible ways to improve and reform federal nutrition programmes; ways that would clean up some of the mess states have made with these programmes,” he said. “However, the bottom lines is that we need to move the legislation.”

But the fate of the legislation isn’t clear after it also met resistance from some Republicans who objected to the cost of the $100bn a year bill – 80% of it on the food stamp programme but also spending on price support to guarantee farmers minimum payments.